Systems, apparatus, and methods for an improved load port

ABSTRACT

Embodiments provide systems, apparatus, and methods for an improved load port that includes a frame supporting a dock and a carrier opener; an elevator operable to raise and lower the carrier opener; an isolation compartment within which the elevator is operable to move, the isolation compartment including a volume isolated from a volume of an equipment front end module (EFEM); and a purge supply within the isolation compartment operable to purge the isolation compartment of reactive gas trapped within the isolation compartment. Numerous additional aspects are disclosed.

RELATED APPLICATION

This application is a divisional application of, and claims priorityfrom U.S. patent application Ser. No. 15/348,967, filed on Nov. 10,2016, and titled “SYSTEMS, APPARATUS, AND METHODS FOR AN IMPROVED LOADPORT” (Attorney Docket No. 24538-04/USA), which is hereby incorporatedby reference herein in its entirety for all purposes.

FIELD

The present application relates to electronic device manufacturingsystems, and more specifically to systems, apparatus, and methods for animproved load port for such systems.

BACKGROUND

Oxygen from a cleanroom can have deleterious effects on substrates(e.g., semiconductor wafers) such as oxidation. Thus, substrates aretypically stored in sealed carriers and/or kept in a non-reactive gas(e.g., nitrogen) environment. Electronic device processing systems useload ports coupled to equipment front end modules (EFEMs) or factoryinterfaces between the cleanroom and the processing tools. Operators ormaterial handling systems can load substrate carriers onto the loadports so the substrates can be loaded into and removed from theprocessing systems. The cleanrooms have oxygen environments for theoperators while the EFEM for the processing systems typically havenitrogen environments to protect the substrates.

Ideally, the EFEM provides a barrier to keep oxygen out of theprocessing system but in some cases, the load port may contribute tooxygen contamination. Thus, what is sought are systems, apparatus, andmethods for an improved load port.

SUMMARY

In some embodiments, a load port system is provided. The system includesa frame supporting a dock and a carrier opener; an elevator operable toraise and lower the carrier opener; an isolation compartment withinwhich the elevator is operable to move, the isolation compartmentincluding a volume isolated from a volume of an equipment front endmodule (EFEM); and a purge supply within the isolation compartmentoperable to purge the isolation compartment of reactive gas trappedwithin the isolation compartment.

In some other embodiments, a load port is provided. The load portincludes an isolation compartment for an elevator defined by a housingand a frame, the isolation compartment including a volume isolated froma volume of an equipment front end module (EFEM) couplable to the loadport; and a purge supply within the isolation compartment operable topurge the isolation compartment of reactive gas trapped within theisolation compartment.

In yet other embodiments, a method for purging an equipment front endmodule (EFEM) system is provided. The method includes flooding an EFEMwith a gas non-reactive to substrates to be passed through the EFEMsystem; and purging an isolation compartment of a load port coupled tothe EFEM of reactive gas trapped within the isolation compartment usinga non-reactive gas supply disposed within the isolation compartment.

Still other features, aspects, and advantages of embodiments will becomemore fully apparent from the following detailed description, theappended claims, and the accompanying drawings by illustrating a numberof example embodiments and implementations, including the best modecontemplated for carrying out the embodiments. Embodiments of may alsobe capable of other and different applications, and its several detailsmay be modified in various respects, all without departing from thescope of the disclosed embodiments. Accordingly, the drawings anddescriptions are to be regarded as illustrative in nature, and not asrestrictive. The drawings are not necessarily drawn to scale. Thedescription is intended to cover all modifications, equivalents, andalternatives falling within the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are block diagrams depicting an example of an electronicdevice processing system according to some embodiments.

FIG. 2A is a front isometric view diagram depicting an example load portwith a lower housing installed according to some embodiments.

FIG. 2B is a front isometric view diagram depicting an example load portwith a lower housing removed according to some embodiments.

FIG. 3 is a rear isometric view diagram depicting an example load portaccording to some embodiments.

FIG. 4 is a rear plan view diagram depicting an example load portaccording to some embodiments.

FIG. 5 is a flowchart illustrating an example method of purging anelectronic device processing system according to some embodiments.

DETAILED DESCRIPTION

Embodiments described herein provide systems, apparatus, and methods foran improved load port to an equipment front end module (EFEM) for anelectronic device manufacturing system. An EFEM typically provides anenclosed environment filled with a gas (e.g., nitrogen) that is notreactive with substrates to be loaded into a processing tool. The EFEMincludes a robot that enables transfer of substrates between thecleanroom environment (e.g., from within sealed substrate carriers via aload port) and the interior of the processing system. In use, the EFEMis ideally maintained in a positive pressure, nitrogen-only environment.However, an airtight seal is not continuously maintained between thecleanroom and the EFEM. For example, during maintenance, oxygen isintroduced into the EFEM to allow personnel to safely enter. Afterward,the EFEM is again flooded with nitrogen to force out remaining oxygen.

The inventors have determined that conventional load ports coupled toEFEMs can trap oxygen which can remain in an isolation compartment ofthe load port and the oxygen can slowly leak out into the EFEM,particularly when the carrier opener of the load port is opened andlowered during substrate transfer from a docked substrate carrier. Theisolation compartment is an enclosed volume within the lower portion ofthe load port within which an elevator translates up and down to lowerand raise the carrier opener of the load port when opening a substratecarrier. The isolation compartment is in fluid communication with theEFEM and the movement of the elevator can push trapped oxygen out of theisolation compartment into the EFEM. In addition, slow leaking of oxygenfrom the isolation compartment of the load port after the EFEM has beenflooded with nitrogen is particularly problematic because the oxygen,which is reactive with substrate materials, can contaminate substratesmoved though the EFEM. Embodiments solve this problem by providing adedicated nitrogen purge supply within the isolation compartment of theload port that is operative to force out the trapped oxygen so theoxygen can be removed when the EFEM is flooded with nitrogen. In someembodiments, a fan within the isolation compartment is used to forceoxygen out of the load port, with or without the dedicated nitrogenpurge supply. In some embodiments, a fan within the EFEM is used to pulloxygen out of the load port, with or without the dedicated nitrogenpurge supply.

Turning to FIGS. 1A and 1B, block diagrams of an example electronicdevice processing system 100 according to some embodiments is shown.FIG. 1B depicts the same system 100 as FIG. 1A but includes a verticaldashed line 101 demarcating the boundary between an oxygen (e.g.,reactive) environment and a nitrogen (e.g., non-reactive) environment.The system 100 includes a substrate processing tool 102 coupled to anEFEM 104. The EFEM 104 is coupled to a load port 105 which includes aframe 106 supporting a docking tray 108, an carrier opener 110, anelevator 112, and an isolation compartment 114 surrounded by a load porthousing 116. The load port housing 116 also encloses a controlcomponents board supporting a controller 118, and an isolationcompartment purge supply 120.

The docking tray 108 is adapted to receive a substrate carrier 122(e.g., a front opening unified pod (FOUP)). The substrate carrier 122 isaccessed via the carrier opener 110 which is lowered out of the way viathe elevator 112 that moves the carrier opener 110 up and down in theEFEM 104, carried by an elevator arm 124 that extends from the elevator112 in the isolation compartment 114. The isolation compartment 114contains the elevator 112. Note that the volume enclosed by load porthousing 116, i.e., the isolation compartment 114, is in fluidcommunication with the EFEM 104 due to an opening (See FIG. 3, 302) formoving elements that extend through the frame 106.

As illustrated by the vertical dashed line 101 in FIG. 1B, elements onthe left side of the system 100 may be maintained in an oxygenenvironment, e.g., a cleanroom, while elements on the right side of thesystem 100 are ideally maintained in a non-reactive gas (e.g., nitrogen)environment. A gas is selected to be non-reactive relative to thesubstrate.

In operation, the EFEM 104 is initially flooded with nitrogen to forceout oxygen. However, oxygen gets trapped in the isolation compartment114 and is purged using the dedicated isolation compartment purge supply120 disposed within the isolation compartment 114. Alternatively oradditionally, isolation compartment 114 (i.e., the volume enclosed bythe load port housing 116) is purged using a fan disposed within theload port housing 116 or is drawn out using a fan or vacuum sourcewithin the EFEM 104 adjacent the isolation compartment 114. Once theoxygen has been flushed out of the EFEM 104, a substrate carrier 122 canbe docked at the load port 105 to deliver or receive substrates to orfrom the substrate processing tool 102. The carrier opener 110 islowered via elevator 112. The substrates are inserted into or removedfrom the substrate carrier 122 via a robot (not shown) and then thecarrier opener 110 is raised to reseal the substrate carrier 122. Shownin phantom in FIGS. 1A and 1B, the controller 118 (including a programedprocessor and memory storing processor executable instructions) withinthe load port housing 116 can be coupled to each of the activecomponents to control operation thereof.

In some embodiments, the purge supply 120 within the isolationcompartment 114 is disposed at a lower end of the isolation compartment114 and arranged to force trapped reactive gas up out of the isolationcompartment 114. In some embodiments, the purge supply 120 within theisolation compartment 114 is disposed at an upper end of the isolationcompartment 114 and arranged to force trapped reactive gas down out ofthe isolation compartment 114. In some embodiments, the isolationcompartment 114 includes a vent opening disposed at an end of theisolation compartment 114 opposite the purge supply 120. The ventopening can include a one-way check valve to allow gas out of theisolation compartment but not back in. In some embodiments, the purgesupply 120 can be replaced with a fan disposed in any of thearrangements described above for the purge supply 120.

FIGS. 2A and 2B depict front isometric views of an example embodiment ofa load port 105. Note that in FIG. 2A, the load port housing 116 isinstalled and in FIG. 2B, the load port housing 116 has been removed.Also note that in FIGS. 2A & 2B, as well as in FIGS. 3 and 4, the samereference numeral is used to reference the same component even when adifferent view of the component is shown. In FIG. 2B, the controlcomponents board 202 mentioned above with respect to FIGS. 1A and 1B, isvisible.

FIG. 3 depicts a back isometric view and FIG. 4 depicts a back plan viewof the example embodiment of a load port 105. The opening 302 to theisolation compartment 114 is clearly shown in these drawings. The volumewithin the isolation compartment 114 is partially isolated from thevolume within the EFEM 104 (FIG. 1) but due to the opening 302 for theelevator arm 124, the isolation compartment 114 is in fluidcommunication with the EFEM 104. Note that the opening 302 is minimizedin order minimize particle migration into the EFEM 104 environment.Thus, there are two volumes separated by opening 302, the EFEM 104environment and the isolation compartment 114 volume. Because there isonly a small opening 302 connecting the two volumes, reactive gas istrapped inside the isolation compartment 114 volume unless a purgesupply 120 is introduced. If trapped oxygen is not purged from theisolation compartment 114, oxygen leaks out into the volume within theEFEM 104, particularly when the elevator 112 moves through the isolationcompartment 114 to lower or raise the carrier opener 110.

In some embodiments, the isolation compartment purge supply 120 providesa non-reactive gas (e.g., nitrogen) at a rate within the range ofapproximately 10 to approximately 100 1 pm and at a pressure within therange of approximately 0.5 in WC to approximately 3 in WC. Other rangesare possible. In some embodiments, an EFEM purge supply (not shown)provides a non-reactive gas (e.g., nitrogen) at a rate within the rangeof approximately 20 1 pm to approximately 1000 1 pm and at a pressurewithin the range of approximately 0.5 in WC to approximately 3 in WC.Other ranges are possible. In alternative embodiments that include afan, a fan can be selected that moves of approximately 10 toapproximately 100 1 pm of gas.

Turning now to FIG. 5, a flowchart depicting an example method 500 ofembodiments is provided. Initially, the substrate processing tool 102side of the system 100 (i.e., the EFEM 104) is flooded with anon-reactive gas (e.g., nitrogen) to force out oxygen (502).Concurrently or after a delay, oxygen trapped in the isolationcompartment 114 is purged using the dedicated isolation compartmentpurge supply 120 (504). Alternatively or additionally, a fan is used topurge the isolation compartment 114 of any trapped oxygen. After theoxygen has been flushed out of the isolation compartment 114 and theEFEM 104, a substrate carrier 122 can be docked at the load port 105(506). Alternatively, a substrate carrier 122 can be docked at the loadport 105 and then the isolation compartment 114 and the EFEM 104 arepurged before opening the substrate carrier 122. The carrier opener 110opens the substrate carrier 122 and is then lowered via elevator 112with the door of the substrate carrier 122 (508). Substrates areinserted into or removed from the substrate carrier 122 and then thecarrier opener 110 is raised to reseal the substrate carrier 122 (510).

Numerous embodiments are described in this disclosure, and are presentedfor illustrative purposes only. The described embodiments are not, andare not intended to be, limiting in any sense. The presently disclosedembodiments are widely applicable to numerous other embodiments, as isreadily apparent from the disclosure. One of ordinary skill in the artwill recognize that the disclosed embodiments may be practiced withvarious modifications and alterations, such as structural, logical,software, and electrical modifications. Although particular features ofthe disclosed embodiments may be described with reference to one or moreparticular embodiments and/or drawings, it should be understood thatsuch features are not limited to usage in the one or more particularembodiments or drawings with reference to which they are described,unless expressly specified otherwise.

The present disclosure is neither a literal description of allembodiments nor a listing of features of the embodiments that must bepresent in all embodiments. The present disclosure provides, to one ofordinary skill in the art, an enabling description of severalembodiments. Some of these embodiments may not be claimed in the presentapplication, but may nevertheless be claimed in one or more continuingapplications that claim the benefit of priority of the presentapplication.

The foregoing description discloses only example embodiments.Modifications of the above-disclosed apparatus, systems and methodswhich fall within the scope of the claims will be readily apparent tothose of ordinary skill in the art. Accordingly, while the embodimentshave been disclosed in connection with exemplary embodiments thereof, itshould be understood that other embodiments may fall within the intendedscope, as defined by the claims.

What is claimed is:
 1. A method for purging an equipment front endmodule (EFEM) system, the method comprising: flooding an EFEM with a gasnon-reactive to substrates to be passed through the EFEM system; andpurging an isolation compartment of a load port coupled to the EFEM ofreactive gas trapped within the isolation compartment using anon-reactive gas supply disposed within the isolation compartment. 2.The method of claim 1 further including supplying the non-reactive gassupply to the isolation compartment through a housing defining theisolation compartment.
 3. The method of claim 1 wherein the trappedreactive gas is oxygen and the non-reactive purge gas is nitrogen. 4.The method of claim 1 wherein purging the isolation compartment is doneconcurrently with flooding the EFEM with the non-reactive gas.
 5. Themethod of claim 1 wherein purging the isolation compartment includesusing a fan.
 6. The method of claim 1 wherein the purge supply withinthe isolation compartment is disposed at a lower end of the isolationcompartment and purging the trapped reactive gas includes forcing thetrapped reactive gas up out of the isolation compartment.